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Real time A/C system help!

Discussion in 'Chit-Chat' started by IdahoDoug, Jul 5, 2005.

  1. IdahoDoug

    IdahoDoug

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    I've got guests in town and their '02 VW Eurovan A/C is acting up. It's been intermittent and now no longer working as they arrived. Here's what I've found:

    Bought gauge and R134 is fully charged.
    When activated, A/C compressor clutch engages and compressor spins as normal with no untoward noises.
    After several minutes, no joy out of the vents - just ambient air.
    The metal lines both remain the same temp, where I'm used to one getting extremely cold in proper operation.
    Low miles (39k) and well cared for. Condensor is clean and no external blockages.

    In other words, externally everything seems normal, but no joy. Anyone seen these symptoms before or have anything to add?

    Thanks,

    DougM
     
  2. fj40crusher

    fj40crusher

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    Maybe the little "blue" button is faulty? Doesn't sound like it's actually turning on the joy.
     
  3. IdahoDoug

    IdahoDoug

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    More data.

    According to the gauge kit, 45psi is the proper fill level. This one shows 105PSI when we first put the gauge on cold with the truck sitting overnight before starting. Then, it crept up to perhaps 110. What's wierd is that it does not change at higher RPMs - which I believe it should. So, perhaps there's an internal blockage/valve failure so the system's at too high an internal pressure so the compressor is unable to overcome the pressure to move freon??

    DougM
     
  4. swank60

    swank60

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    Here's the rub on your guage reading, if I'm reading what you say right:

    First, your reading is always WAY high if the compressor is NOT running. Once you start the vehicle and turn on the compressor, with the AC on max cold/full blast, the psi reading should drop to something more normal - 35 to 45 psi.

    In my 60, when the AC first started acting up (R12) it was the expansion valve that was stuck. Thing is I'm not sure if more up-to-date vehicles use expansion valves, but there has to be something that does the same thing in the system...not sure what that is, though.
     
  5. IdahoDoug

    IdahoDoug

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    Swank,

    Yeah, you're right on there with the pressure problem. Looks like it's going to have to go to the dealer as it will be a compressor or other internal widget. Thanks for the excellent real time help! Also appreciated the emails....

    No further needed.

    DougM
     
  6. Dragon158

    Dragon158

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    I'm a little late here, but the 105PSI while the engine is off sounds normal. If I read you right that is? An average reading on the low side gauge should be any where between 20 & 35PSI, High side readings anywhere between 190 & 230PSI. These are obviously ballpark figures. But with the engine off the pressure will equalize, low and high side pressures will be the same. Sounds like a possible expansion vale or oriface (SP?) tube. I'm not sure what VW uses.
    Hope that helped.
     
  7. Texican

    Texican s-Moderator

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    Give me both readings on the gauges, hi and low side, without both you are pissing in the wind.
    Butch